How Trump is Changing Forecasters’ Minds

The election of Donald Trump as the 45th President of the United States surprised many forecasters on GJ Open and around the world. After any forecasting surprise, an aspiring Superforecaster should reflect on why they might have been wrong, which signs they might have missed, and importantly, whether an event signals that they should update their beliefs about other events.

And in proper Superforecasting form, GJ Open forecasters quickly began updating their forecasts on other questions in the days following Mr. Trump’s victory. Which questions saw the largest changes in the consensus forecast? The answer to that question shows how forecasters expect the world will change course under President Trump.

It’s no surprise that forecasters believe the chances of the U.S. imposing economic sanctions on Iran for their nuclear program are rising, given Mr. Trump’s strong criticism of the 2015 agreement that removed sanctions. The chances of new sanctions being imposed before November 1, 2017 rose from 3% on the morning of the election to a high of 45% in December before settling around the current probability of 35%. As GJ Open forecaster and self-described “foresight skeptic” DBrownian describes, it would be quite easy for President Trump to reimpose sanctions by simply not renewing their relief:

The chances of the U.S. endorsing a peace plan in Syria before July 1, 2017 which allows Bashar Al-Assad to remain in power followed a similar trajectory, rising from 5% on November 8th to 40% in late November, then falling slightly down to 35% today. GJ Open forecaster Greyowlsova pointed out that such a plan aligns with a priority of fighting ISIS, something discussed publicly by several of Mr. Trump’s nominees for national security jobs:

Yes, many people on this board are right. Presidential powers are balanced by other institutions and limited. But that is mainly in domestic policies, with their multiple interest groups.

In foreign affairs, the President has much more freedom. Besides, what Trump has been talking, does make sense and is easier and more predictable – what happens to Syria if Assad goes? Most probably a continuing disaster. Fighting ISIS is more important to US than Assad.

Also following Trump’s election, forecasters quickly indicated that any remaining chances of a new Supreme Court Justice being appointed before Inauguration Day had been eliminated.

While the confirmation of President Obama’s nominee Judge Merrick Garland (or any other Obama appointee) was already seen as an unlikely scenario, the consensus probability of an appointment quickly fell from 10% on election day to 0% on November 26th. Senate Republicans’ plan to delay Garland’s nomination until after the election in the hopes that Mr. Trump would win and nominate a more conservative justice paid off. Judge Garland’s nomination officially expired earlier this week.

GJ Open forecasters also saw large changes in the likely outcome of questions unrelated to U.S. domestic or foreign policy. Most notably, the odds that the next president of France would be a member of the populist right-wing National Front party rapidly increased following the news of Mr. Trump’s victory.

Before the U.S. election, forecasters thought that National Front president Marine Le Pen was as likely to win the upcoming French election as incumbent President François Hollande, each of whom was given an 11% chance on election day (Hollande later announced he would not run for re-election). Soon after the U.S. election, Le Pen’s chances rose to a high of 37% in late November before settling around the current consensus probability of 29%. The National Front’s gain in the probability of winning was entirely offset by a loss in the chances of the Republicans, who nominated François Fillon as their candidate later in November.

Many forecasters see Mr. Trump’s election as intricately tied to a global wave of populism that resulted in the U.K.’s vote to leave the European Union and makes Le Pen’s odds of winning the French presidential election much more likely, as GJ Open forecaster Rhiannon explained in the days after the U.S. election:

Brexit → Trump → Le Pen
Not only did Brexit make Trump more likely – in the sense that it demonstrated the existence of a demographic favoring radical change from the status quo – but also Trump supporters were emboldened by Brexit. Farage helped Trump craft his message in the final weeks of the campaign. The same may be true for France – Trump and Brexit make Le Pen supporters believe they have a real chance and will motivate them to seize the opportunity. Hollande is deeply unpopular; the political cycle demands a stark change from him. Juppe and Sarkozy are now part of the established political class, and that may prove unpopular too.

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